PINTO, Spain -- Three-time Tour de France champion Alberto Contador challenged cycling authorities Saturday to freeze his urine and blood samples until technology can show he rode clean in this year's race and disprove his positive test for clenbuterol.
In an interview with The Associated Press, Contador stuck to his story that contaminated meat is the cause of his positive test on July 21 for the fat-burning and muscle-building drug.
"I can tell you I am not a scientist but I can also tell you that all my urine and all my blood samples are in the lab, and I call for them to be analyzed as many times as necessary to clear up this case," Contador said. "If it is necessary to freeze either my urine or my blood samples so that five years from now, when the system has been further perfected, it can be analyzed, I authorize this."
During the Tour, the samples are given to cycling's governing body. But the International Cycling Union is not obliged to freeze them, although it has that option.
Contador was provisionally suspended Thursday by the UCI after a small amount of clenbuterol was discovered in his urine sample by a laboratory in Cologne, Germany.
If he is found guilty of doping, he faces the loss of this year's Tour de France title and a possible two-year ban.
The same lab also found plastic residues that might turn up after a transfusion of blood from a plastic bag, according to news reports in France and Germany.
Contador said he hasn't been informed of any such find, and vehemently denies any suggestions he underwent a transfusion with his own blood to receive an energy boost before a grueling mountain stage July 22.
As the Tour leader, Contador said he underwent tests of his blood and urine eight times in the last week of the race -- a frequency he describes as unprecedented in cycling history.
WADA director-general David Howman says any positive test containing only trace amounts of a banned substance should still be taken seriously.
"[Just because] a small amount is detected, it doesn't mean you weren't cheating," Howman said from the Commonwealth Games in New Delhi.
Eating meat on a cycling rest day is unusual, and Spanish health authorities say clenbuterol cannot be used on animals destined for human consumption. It is sometimes used illegally to speed up growth and increase muscle mass in chickens, cattle and pigs.
Contador said he understands it might be difficult for his story to be accepted in a sport tainted by doping scandals, but insists it is the truth.
"There will be people who believe it more, who have more trust, and others who believe it less," Contador said in the 15-minute interview from his hometown of Pinto, outside Madrid.
Contador wished he had a sample of the beef he ate July 20 and July 21 so the presence of clenbuterol could be proven.
"Boy, do I wish I had a piece of that meat so it could analyzed in a laboratory with the level of precision of the one in Cologne," Contador said. "That is now something that is totally impossible to prove."
UCI president Pat McQuaid called on Spain's government to do more to tackle doping after four Spanish riders were suspended in the past week for doping offenses.
McQuaid, in Geelong, Australia, for the world road cycling championships Saturday, said too many doping cases came out of Spain and the nation's government appeared to be ignoring the problem.
He refused to comment specifically about Contador, but said cycling had suffered a "big hit" from the positive tests reported in the past week. In the latest case, the UCI provisionally suspended Olympic medalist Margarita Fullana on Saturday for using the banned blood booster EPO.
"There is a problem in Spain because ... a large percentage of our doping cases come from Spain," McQuaid said. "There doesn't seem to be, so far, the will to tackle that in Spain and that really needs to come from the government down."
Tour of Spain runner-up Ezequiel Mosquera and teammate David Garcia da Pena were also suspended after positive tests for hydroxyethyl starch.
Information from The Associated Press was used in this report.